scholarly journals Regulation of Flagellar Assembly by Glycogen Synthase Kinase 3 in Chlamydomonas reinhardtii

2004 ◽  
Vol 3 (5) ◽  
pp. 1307-1319 ◽  
Author(s):  
Nedra F. Wilson ◽  
Paul A. Lefebvre
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Glycogen Synthase ◽  
Lithium Treatment ◽  
Active Form ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Dependent Manner ◽  
Flagellar Assembly ◽  
Flagellar Proteins

ABSTRACT Chlamydomonas reinhardtii controls flagellar assembly such that flagella are of an equal and predetermined length. Previous studies demonstrated that lithium, an inhibitor of glycogen synthase kinase 3 (GSK3), induced flagellar elongation, suggesting that a lithium-sensitive signal transduction pathway regulated flagellar length (S. Nakamura, H. Takino, and M. K. Kojima, Cell Struct. Funct. 12:369-374, 1987). Here, we demonstrate that lithium treatment depletes the pool of flagellar proteins from the cell body and that the heterotrimeric kinesin Fla10p accumulates in flagella. We identify GSK3 in Chlamydomonas and demonstrate that its kinase activity is inhibited by lithium in vitro. The tyrosine-phosphorylated, active form of GSK3 was enriched in flagella and GSK3 associated with the axoneme in a phosphorylation-dependent manner. The level of active GSK3 correlated with flagellar length; early during flagellar regeneration, active GSK3 increased over basal levels. This increase in active GSK3 was rapidly lost within 30 min of regeneration as the level of active GSK3 decreased relative to the predeflagellation level. Taken together, these results suggest a possible role for GSK3 in regulating the assembly and length of flagella.

scholarly journals Glycogen Synthase Kinase 3-Dependent Phosphorylation of Mdm2 Regulates p53 Abundance

2005 ◽  
Vol 25 (16) ◽  
pp. 7170-7180 ◽  
Author(s):  
Roman Kulikov ◽  
Karen A. Boehme ◽  
Christine Blattner
Keyword(s):  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Tumor Suppressor Protein ◽  
Glycogen Synthase Kinase 3 ◽  
Dependent Manner ◽  
Mdm2 Protein ◽  
Conserved Domain ◽  
P53 Tumor Suppressor Protein

ABSTRACT The Mdm2 oncoprotein regulates abundance and activity of the p53 tumor suppressor protein. For efficient degradation of p53, Mdm2 needs to be phosphorylated at several contiguous residues within the central conserved domain. We show that glycogen synthase kinase 3 (GSK-3) phosphorylated the Mdm2 protein in vitro and in vivo in the central domain. Inhibition of GSK-3 rescued p53 from degradation in an Mdm2-dependent manner while its association with Mdm2 was not affected. Likewise, inhibition of GSK-3 did not alter localization of p53 and Mdm2 or the interaction of Mdm2 and MdmX. Ionizing radiation, which leads to p53 accumulation, directed phosphorylation of GSK-3 at serine 9, which preceded and overlapped with the increase in p53 levels. Moreover, expression of a GSK-3 mutant where serine 9 was replaced with an alanine reduced the accumulation of p53 and induction of its target p21WAF-1. We therefore conclude that inhibition of GSK-3 contributes to hypophosphorylation of Mdm2 in response to ionizing rays, and in consequence to p53 stabilization.

scholarly journals GSK-3β in Pancreatic Cancer: Spotlight on 9-ING-41, Its Therapeutic Potential and Immune Modulatory Properties

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 610
Author(s):  
Robin Park ◽  
Andrew L. Coveler ◽  
Ludimila Cavalcante ◽  
Anwaar Saeed
Keyword(s):  
Pancreatic Cancer ◽  
Therapeutic Potential ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
In Vivo Models ◽  
Gsk 3Β ◽  
Early Phase Clinical Trials

Glycogen synthase kinase-3 beta is a ubiquitously and constitutively expressed molecule with pleiotropic function. It acts as a protooncogene in the development of several solid tumors including pancreatic cancer through its involvement in various cellular processes including cell proliferation, survival, invasion and metastasis, as well as autophagy. Furthermore, the level of aberrant glycogen synthase kinase-3 beta expression in the nucleus is inversely correlated with tumor differentiation and survival in both in vitro and in vivo models of pancreatic cancer. Small molecule inhibitors of glycogen synthase kinase-3 beta have demonstrated therapeutic potential in pre-clinical models and are currently being evaluated in early phase clinical trials involving pancreatic cancer patients with interim results showing favorable results. Moreover, recent studies support a rationale for the combination of glycogen synthase kinase-3 beta inhibitors with chemotherapy and immunotherapy, warranting the evaluation of novel combination regimens in the future.

The active form of glycogen synthase kinase-3? is associated with granulovacuolar degeneration in neurons in Alzheimer's disease

2002 ◽  
Vol 103 (2) ◽  
pp. 91-99 ◽  
Author(s):  
Allal Boutajangout ◽  
Karelle Leroy ◽  
Authelet M. ◽  
Brian Anderton ◽  
Jean-Pierre Brion ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Glycogen Synthase ◽  
Active Form ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Granulovacuolar Degeneration

scholarly journals Multiple mechanisms for the phosphorylation of C-terminal regulatory sites in rabbit muscle glycogen synthase expressed in COS cells

1996 ◽  
Vol 313 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Alexander V. SKURAT ◽  
Peter J. ROACH
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Rabbit Muscle ◽  
Cos Cells ◽  
Additional Mutation ◽  
Regulatory Sites

Glycogen synthase can be inactivated by sequential phosphorylation at the C-terminal residues Ser652 (site 4), Ser648 (site 3c), Ser644 (site 3b) and Ser640 (site 3a) catalysed by glycogen synthase kinase-3. In vitro, glycogen synthase kinase-3 action requires that glycogen synthase has first been phosphorylated at Ser656 (site 5) by casein kinase II. Recently we demonstrated that inactivation is linked only to phosphorylation at site 3a and site 3b, and that, in COS cells, modification of these sites can occur by alternative mechanisms independent of any C-terminal phosphorylations [Skurat and Roach (1995) J. Biol. Chem. 270, 12491-12497]. To address these mechanisms multiple Ser → Ala mutations were introduced in glycogen synthase such that only site 3a or site 3b remained intact. Additional mutation of Arg637 → Gln eliminated phosphorylation of site 3a, indicating that Arg637 may be important for recognition of site 3a by its corresponding protein kinase(s). Similarly, additional mutation of Pro645 → Ala eliminated phosphorylation of site 3b, indicating a possible involvement of ‘proline-directed’ protein kinase(s). Mutation of Arg637 alone did not activate glycogen synthase as expected from the loss of phosphorylation at site 3a. Rather, mutation of both Arg637 and the Ser → Ala substitution at site 3b was required for substantial activation. The results suggest that sites 3a and 3b can be phosphorylated independently of one another by distinct protein kinases. However, phosphorylation of site 3b can potentiate phosphorylation of site 3a, by an enzyme such as glycogen synthase kinase-3.

scholarly journals Priming-Dependent Phosphorylation and Regulation of the Tumor Suppressor pVHL by Glycogen Synthase Kinase 3

2006 ◽  
Vol 26 (15) ◽  
pp. 5784-5796 ◽  
Author(s):  
Alexander Hergovich ◽  
Joanna Lisztwan ◽  
Claudio R. Thoma ◽  
Christiane Wirbelauer ◽  
Robert E. Barry ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Glycogen Synthase ◽  
Human Cancer ◽  
Suppressor Gene ◽  
Binding Activity ◽  
Glycogen Synthase Kinase ◽  
Normal Operation ◽  
Glycogen Synthase Kinase 3

ABSTRACT Inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene is linked to the development of tumors of the eyes, kidneys, and central nervous system. VHL encodes two gene products, pVHL30 and pVHL19, of which one, pVHL30, associates functionally with microtubules (MTs) to regulate their stability. Here we report that pVHL30 is a novel substrate of glycogen synthase kinase 3 (GSK3) in vitro and in vivo. Phosphorylation of pVHL on serine 68 (S68) by GSK3 requires a priming phosphorylation event at serine 72 (S72) mediated in vitro by casein kinase I. Functional analysis of pVHL species carrying nonphosphorylatable or phosphomimicking mutations at S68 and/or S72 reveals a central role for these phosphorylation events in the regulation of pVHL's MT stabilization (but not binding) activity. Taken together, our results identify pVHL as a novel priming-dependent substrate of GSK3 and suggest a dual-kinase mechanism in the control of pVHL's MT stabilization function. Since GSK3 is a component of multiple signaling pathways that are altered in human cancer, our results further imply that normal operation of the GSK3-pVHL axis may be a critical aspect of pVHL's tumor suppressor mechanism through the regulation of MT dynamics.

scholarly journals Glycogen Synthase Kinase 3 Inhibition Promotes Adult Hippocampal Neurogenesis in Vitro and in Vivo

2012 ◽  
Vol 3 (11) ◽  
pp. 963-971 ◽  
Author(s):  
Jose A. Morales-Garcia ◽  
Rosario Luna-Medina ◽  
Sandra Alonso-Gil ◽  
Marina Sanz-SanCristobal ◽  
Valle Palomo ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3

scholarly journals The mechanism by which epidermal growth factor inhibits glycogen synthase kinase 3 in A431 cells

1994 ◽  
Vol 303 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Y Saito ◽  
J R Vandenheede ◽  
P Cohen
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
A431 Cells ◽  
S6 Kinase ◽  
P70 S6 Kinase ◽  
Epidermal Growth

Glycogen synthase kinase 3 (GSK3) was inhibited by 50% within 5 min when A431 cells were stimulated with epidermal growth factor (EGF). The inhibition was unaffected by rapamycin at concentrations which blocked the activation of p70 S6 kinase, and reversed by incubation with protein phosphatase-1. EGF stimulation of A431 cells inhibited GSK3 alpha and GSK3 beta to a similar extent, and inhibition was accompanied by phosphorylation of the tryptic peptides containing the serine residues phosphorylated in vitro by p70 S6 kinase or MAP kinase-activated protein (MAPKAP) kinase-1 beta (also termed Rsk-2). These results demonstrate that EGF inhibits GSK3 by inducing phosphorylation of a serine residue and that GSK3 is not phosphorylated in vivo by either p70 S6 kinase or protein kinase C.

scholarly journals Convergence of Multiple Signaling Cascades at Glycogen Synthase Kinase 3: Edg Receptor-Mediated Phosphorylation and Inactivation by Lysophosphatidic Acid through a Protein Kinase C-Dependent Intracellular Pathway

2002 ◽  
Vol 22 (7) ◽  
pp. 2099-2110 ◽  
Author(s):  
Xianjun Fang ◽  
Shuangxing Yu ◽  
Janos L. Tanyi ◽  
Yiling Lu ◽  
James R. Woodgett ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Lysophosphatidic Acid ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Hek293 Cells ◽  
Glycogen Synthase Kinase 3 ◽  
Kinase C ◽  
Pkc Inhibitors

ABSTRACT Lysophosphatidic acid (LPA) is a natural phospholipid with multiple biological functions. We show here that LPA induces phosphorylation and inactivation of glycogen synthase kinase 3 (GSK-3), a multifunctional serine/threonine kinase. The effect of LPA can be reconstituted by expression of Edg-4 or Edg-7 in cells lacking LPA responses. Compared to insulin, LPA stimulates only modest phosphatidylinositol 3-kinase (PI3K)-dependent activation of protein kinase B (PKB/Akt) that does not correlate with the magnitude of GSK-3 phosphorylation induced by LPA. PI3K inhibitors block insulin- but not LPA-induced GSK-3 phosphorylation. In contrast, the effect of LPA, but not that of insulin or platelet-derived growth factor (PDGF), is sensitive to protein kinase C (PKC) inhibitors. Downregulation of endogenous PKC activity selectively reduces LPA-mediated GSK-3 phosphorylation. Furthermore, several PKC isotypes phosphorylate GSK-3 in vitro and in vivo. To confirm a specific role for PKC in regulation of GSK-3, we further studied signaling properties of PDGF receptor β subunit (PDGFRβ) in HEK293 cells lacking endogenous PDGF receptors. In clones expressing a PDGFRβ mutant wherein the residues that couple to PI3K and other signaling functions are mutated with the link to phospholipase Cγ (PLCγ) left intact, PDGF is fully capable of stimulating GSK-3 phosphorylation. The process is sensitive to PKC inhibitors in contrast to the response through the wild-type PDGFRβ. Therefore, growth factors, such as PDGF, which control GSK-3 mainly through the PI3K-PKB/Akt module, possess the ability to regulate GSK-3 through an alternative, redundant PLCγ-PKC pathway. LPA and potentially other natural ligands primarily utilize a PKC-dependent pathway to modulate GSK-3.

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